Charcot Marie Tooth Disease

Question 1

CMT 2 categories

Answer 1

Neuropathy is primary disorder

Neuropathy is part of a larger multi system disorder

Question 2

CMT

Answer 2

Initially involves peroneal nerve and eventually affects muscles in foot and lower leg
Later progresses on to forearm and hands

Question 3

CMT etiology

Answer 3

Autosomal dominant

Chromosomal deficits create duplication, deletion, or point mutations in code for proteins invovled in myelination

Question 4

Two main subtypes of heterogenous polyneuropathy CMT

Answer 4

CMT1 (most common autosomal dominant pattern)

CMT2

Question 5

CMT 1A

Answer 5

Primary 70% cases
Segmental demyelination of peroneal nerve

Ave NCV 15-20 m/s
(Normal ~40m/s)

Question 6

CMT1B

Answer 6

5-10% of type 1

NCV <20

Question 7

CMT1C

Answer 7

Dejerine stoats disease
Severe demyelination which can be detected by measuring NCV (266-42)
Autosminal dominant usually in infancy

Question 8

CMT1D

Answer 8

NCV 15-20m/s

Question 9

CMT1 foot structure

Answer 9

Pes cavus

Question 10

CMT patho

Answer 10

Mutations in proteins responsible for Schwann cell myelination —> extensive demyelination and hypertrophic Schwann cell (onion bulb)—> enlarged peripheral nerves

Question 11

CMT2

Answer 11

Less common,
20-40% CMT pts
Autosomal dominant w/ main affect on axon
NCV slightly below normal generally above 38

Question 12

CMT2 associated w/

Answer 12

Mutation in myelin protein zero
Genetic mutations that disrupt neurofimalment assembly—> affect axon transport
Loss of anterior horn cells in lumboscarcal seg of SC and cell bodies in dorsal root ganglion—> axonal degeneration

Question 13

CMT2 onset

Answer 13

B/n 2nd and 7th decade

Less involvement of small muscle of hands than CMT1

Question 14

CMT diagnostic

Answer 14

History
Hereditary 
Clinical presentations
EMG and NCV
Nerve biopsy

Question 15

Distinguish b/n CMT1 and CMT2

Answer 15

Clinically impossible

Question 16

CMT degrees of genetic dominance

Answer 16

Graded presentation

Linked (CMT2), men have signs of both demyelination and axonal degneration

Question 17

CMT1 onset and progression

Answer 17

Slow and childhood

Question 18

CMT s/s include

Answer 18

Distally symmetric muscle weakness, diminished DTR
Feet have pes cavus and hammer toes
High stepage gait secondary to DF and Evertor weakness

Question 19

As CMT progresses

Answer 19

Weakness and wasting of intrinsic muscles of hands and eventually forearms

Question 20

CMT1 presents

Answer 20

Demyelinates the peripheral nerve resulting in proprioceptive loss in feet and ankles and diminsihed cutaneous sensation

Question 21

CMT 2 presents

Answer 21

W/ minimal sensory loss

Sensory symptoms can also include tingling and burning in feet and legs

Question 22

CMT tx

Answer 22

No specific tx to alter course of disease
Tx is symptomatic to ensure fx maintained
Stretching and positioning is critical to maintain muscle length and joint mobility

Question 23

PT intervention

Answer 23

Focused on endurance and strength training

Home based PRE, cycling, strength endurance

Question 24

PT outcomes

Answer 24

Improved ADLS
Gait speed
Knee torque
Subjective pain and fatigue
VO2 max

Question 25

CMT most promising tx

Answer 25

Pharmacology targeting genetic mutations

Anti cancer drug should be avoided and can cause exacerbation

Question 26

CMT prognosis

Answer 26

Slowly progressive-manage impairments as they arise

Question 27

IF CMT not managed

Answer 27

Contracture
Progressive gait abnormalities
Falls and secondary injuries
Pressure sores
Functional decline